Yes but if you want to know an arrays length you can just put it in a scalar. So you consume some API and want to get the length of the result. You put the array result into a scalar variable. Then what this is not the length?
Perl is well known for it's multitude of idiosyncrasies, this is one of the reasons why it can be frustrating to programmers who have better experience in more modern or rigidly structured languages.